Austin Audio Work Black Amp Review: Chain: Pi2AES --> Bifrost 2/Matrix Sabre Pro (XLR) --> Black Amp Amps: Elekit TU-8600s, SW51+, Jotunheim 2 Headphones: ZMF VO/Auteur, HD650, Focal Elex, Verum One Amp build: Train of thought that follows is all subjective. What I do wish for would be that the case was made of sturdier materials. The Black Amp has a WW2 era control box charm to it but the outside case looks like it can easily be scratched. The demo build may be different than what's offered in production. Different manufacturers have different costs/machines but at $1500 I'd expect something along the lines of the metal casing or to feel more premium. As a comparison the SW51+ which is $350+ comes in a hefty metal case. The case doesn't do the amp justice with the great sound coming out of it. Sound: I was surprised at how tubey sounding the amp is. When paired up with the Bifrost 2, it brought back memories of the Glenn OTL. The Black Amp has more characteristics of a tube amp than either the SW51+ and the even the ZMF Pendant with the default tubes. While the SW51+ and the Pendant lean more towards the SS sound (more incisive, livelier) the Black Amp goes a bit more the opposite way. It has a very open sound stage, instruments never feel like they're squished together and instead have plenty of space between each other. There is no compression here compared to other amps and layering is also fantastic. It displays a non-fatiguing sound that tube amps excel at without smothering details. It retains enough treble sparkle but plays the tube act where it's not digital sounding or sharp. I mean it sounds analog but in a good way. The sound stage is wider and slightly deeper than either the SW51+ and Jotunheim 2. Notes have some nice weight to it and also display a 3D rounded effect that again, tube amps excel at. Notes also are taller/larger compared to amps like SW51+ and Jotunheim 2. Really, this is a tube amp at heart but without most of the drawbacks of tube amp. I have no complaints about the amps PRaT. It never felt slow or off tempo. The amp sound stage is what I consider neutral. It's not pushed forward or back. I think the few nitpicks that I can complain about is how solid the images are and slam. The outside of images are slightly more nebulous than what you would get on any of the amps I'm comparing it to and slam can depend on the headphone. The Verite Open has great slam with this amp but the Auteur's slam is more muted than say with it paired to a Pendant. Also, some headphones may not play not with the Z-out pot in the back. As much as I wanted to really like Elex with the setting on the lowest-Z, it always felt too thick. Pairings / Synergy / Comparisons: DACS Bifrost 2: This is the pairing if you want meatier weight behind notes and a 3D image of instruments. It's not the best for thicker sounding headphones but I enjoyed it with all of my high ohm headphones. The Auteurs with this pairing put a big smile on my face. Matrix Sabre Pro: This is the pairing you want to go with (DS DAC) if you're looking for a more livelier, incisive sound. It does great to bring it back to neutral and not sound as warm. Transients are sharper but at the sacrifice of sound stage width. Notes are also flatter. Amps: Elekit TU-8600s: The Elekit build that I have is around $3000+ give or take. The Black Amp gets close to the sound of the this amp except the Elekit resolves instruments better, the sound stage stage is wider and deeper. Reverbs, small spatial queues, and microdynamics were hard to distinguish between both amps. There's more slam with the TU-8600s and the amp is slightly more incisive. I do enjoy the mids more with both ZMF headphones from the TU-8600s than with the Black Amp. Versatility goes to the TU-8600 as it doubles a headphone/speaker amp. You can also go out from the speaker taps to provide more current to harder to drive headphones. One thing to note is that my particular amp does not like to have a preamp (Sys+) with the PC being the source. It picks up the video card noise, spool up and down of the fan, and buzzing in the background. This doesn't happen with the Black Amp. SW51+: The Black Amp is a much tubier sounding amp than the SW51+. It has a bigger, open, and deeper sound stage. SW51+ is more incisive and livelier than the Black Amp. Images are taller on the Black Amp, resolves better, and, does better at layering. I enjoyed the Auteurs and Verite Open more out of Black Amp than the SW51+. The Focal Elex is sticking to the SW51+ as I didn't like how thick it sounded with either DAC. Jotunheim 2: So I think the Black Amp is what would of loved the Jotunheim 2 to sound like. The Jot 2 slightly out resolves it. Also, the power to drive Orthos may be a deal breaker compared to the Black Amp. The Verum One ran "ok" on the Black Amp but it sounded much better out of the Jot 2. Again, the Black Amp beats the lower priced amps in depth and width. I think if you're running high-z headphones then really consider the Black Amp for the price. If you run everything in between then the Jotunheim 2 will be the better all rounder. Headphones Verite Open: I enjoyed the synergy between the Black Amp and this headphone. At first it was hard to distinguish between the TU-8600s and the Black Amp. After critically listening the slam was the first give away, the instrument resolve was the second give away, and sound stage depth was the last give away. Really, I could swing to either as they both sound great with each other. For all the other amps I'd pick the Black Amp hands down. The pairing with the Matrix Sabre Pro was great with this headphone, and the punchiness of this headphone works well with the Black Amp. Auteur: The Black Amp fed by the Bifrost 2 with the Auteurs by far was one of my favorite pairings. The timbre of instruments, the open nature of the amp, with the thickness of instruments reminded me of the Glenn OTL. I caught myself going back to this pairing and by the end of the loaner. The Jotunheim 2 does well to bring it back to neutral but there was a more emotional connection with the Black Amp. You just want to sit back, grab some whiskey, and listen to tunes. I listened to this pairing exclusive on the last day of the loaner before packing it up and sending it back. Elex: I enjoyed how the amp made his headphone non-fatiguing but thought it was too thick in the end. I very much enjoyed this out of either the SW51+ or the Jotunheim 2. The amp did create the sense of out of head experience compared to either amp. It added more width and depth than either amp could. Verum One: Stick with a solid state amp like the Jotunheim 2. Conclusion: Yeah I really liked this amp and was bummed when it left. I think it kills in sound in it's price category if you're looking for a tube sounding amp without having to deal with tubes. It works really well with higher-z headphones, it's ok with planars, and can be too thick sounding with lower-z dynamics cans. If they can improve the case and the slam it would be an even better proposition.